Resins of the kind called vinyl ester resins herein, when combined with catalysts and accelerators, have relatively short gel times, i.e., the time from addition of the catalyst to the setting up of the resin. However, with some conventional accelerators, e.g., N,N-dimethyl aniline, gel time may increase with time when the resin/accelerator system is stored (hereinafter referred to as gel time drift). Such systems become unworkable or impractical for extended periods of time. Other accelerators, such as cobalt naphthenate, decrease the resin storage life, i.e., the time until the resin (without catalyst) begins to set-up or gel.
It would be desirable to have an accelerator that can be added to the vinyl ester resin which would not show gel time drift on storage and at the same time would have good storage life. With such an accelerator, pre-accelerated resins could be produced which could be shipped to job sites where the addition and mixing of accelerators is difficult and subject to error. At the present time, N,N-dimethyl aniline is one of the most commonly used accelerators but because of the gel time drift during storage it is in many instances mixed with resin just before use and in quantities only sufficient for the immediate job.